1. Field of the Invention
This invention generally relates to vehicle-mounted, navigational guidance and image capturing systems, and the means for improving their portability and usability. More particularly, this invention relates to devices capable of detecting and interpreting visual information in the vicinity of a vehicle.
2. Description of the Related Art
There exist many types of vehicular navigational systems. The most sophisticated of these utilize local-area, digitized-road-map systems with video monitors which display a map portion of interest and a cursor that indicates the position of the driver's vehicle within the map portion of interest. The position of the vehicle is typically determined by using either a combination of a wheel-sensor odometer and a compass or the reception of electric signals from global positioning system (GPS) satellites. Using such a digitized map, the driver can locate departure and destination points on the map, and then visually follow the displayed map as the driver travels towards the desired destination point. During this travel, the portion of the map that is displayed is periodically adjusted to keep the cursor representing the driver's current position within the displayed map portion.
Several recent U.S. patents have been directed towards inventions to provide such navigation aids or to improve upon the various components of existing systems. For example, U.S. Pat. No. 5,552,990 discloses an improved vehicle position detecting apparatus that utilizes tire rotation and bearing sensors, along with techniques for compensating for road map errors, to compute the current position of the vehicle.
U.S. Pat. No. 5,652,706 discloses a vehicle navigation system that utilizes global positioning system (GPS) data along with sensors for monitoring tire rotation to determine the current position of the vehicle. This system includes a computer with an arithmetic section that, in the event the driver deviates from an initially identified optimum route, researches from stored, local area map data the shortest distance route back to the optimum route, with preference being given to those routes which avoid the driver having to make a U-turn. This system also includes an optional vocal control section that can provide voice guidance for the driver.
U.S. Pat. No. 5,642,106 discloses a visual incremental turn detector. This patent suggests that such a camera might be combined with an odometer and a CD-ROM device, for storing digitized video information obtained by driving an associated vehicle over a known course, in order to allow the subsequent determination of the present position of an automobile traveling along this same course. These elements are then described as being combinable with a computer and a video monitor or audio speaker to communicate navigation instructions to the driver.
U.S. Pat. No. 5,544,060 discloses a vehicle navigation system that sequentially outputs updated path information, based on a calculated optimal path, in accordance with the determined present position of the vehicle. This determination is described as being made by utilizing an axle sensor and a geomagnetic (or bearing) sensor. The path information is given by a microprocessor-generated videographical directional indicator that displays turn icons, along with pertinent road names and indications of the distance to be traveled before making the next scheduled turn. Similarly, U.S. Pat. No. 5,654,892 describes the improvement that consists of allowing for the display of more complex icons that indicate various road anomalies along with turn directions.
U.S. Pat. No. 5,646,856 describes a vehicle navigation system including means for storing data representing a route to be followed; means for detecting an actual position of and the actual path traveled by the vehicle; comparison means for comparing the actual position of the vehicle to the route to be followed; and means responsive to said comparison means for giving direction commands to the vehicle operator; and particularly manually operable means for inputting data representing a desired route. The means disclosed for detecting an actual position of the vehicle consists of "angle sensors and sensors on the vehicle wheels." By obeying the direction commands, the operator is able to steer the vehicle along the selected route. The advantage cited for this system is that it does not require a route search algorithm or an extended database and is therefore less complex and less expensive to produce than previously known systems.
U.S. Pat. No. 5,504,482 discloses an optional electro-optical obstacle detection system which is part of a larger automobile navigation guidance, control and safety system.
In terms of the mounting of a device so that it is visible to a vehicle operator but does not interfere with the operator's field of view, U.S. Pat. Nos. 5,667,176, 5,631,638, 4,625,210 and 4,896,855 disclose various mounting arrangements.
None of these vehicle navigation systems are proactive. Most of them require a driver to repetitively study a displayed map, thereby diverting attention away from the road and the safe operation of the automobile.
In general, these prior art systems can be classified into three major types. The first type consists of built-in systems in which the systems are designed into a new vehicle at the factory. The second type consists of after-market adds-on devices in which the devices are securely added to the vehicles after the vehicles are on the ground. The third type consists of those that run on portable computers with a GPS devices attached to the such computers. Even though there are advantages in all these systems, there are significant disadvantages in all them.
The main problem with the built-in systems are their high cost-to-usage ratio. Because they are hardwired into the vehicle and thus cannot be moved from one vehicle to the next, such systems often sit idle most of the time. Furthermore, they are usually dedicated to the single purpose of providing navigational assistance, a need that most people experience only occasionally. And, they are usually only available on the more expensive vehicles.
The main problem with most of the adds-on type navigational systems is that they tend to alter the inside look of the vehicles and also require installations that are often destructive to the vehicles, such as drilling a number of holes on the floor pan of the vehicles in order to allow the system's equipment be held securely while the vehicle is in motion. Once installed, the equipment takes up valuable space and often gets in the way of operator when the system is not in use.
The main problem with the navigation systems utilizing GPS devices with portable computers that the use of such systems can often create a hazardous situation for their users. Such situations arise because it is often difficult to find an easily observable place in the vehicle where portable computer can be securely fastened. So, unless there is a companion traveling with the vehicle operator who can hold and operate the portable computer, the use of such navigation systems may be ill-advised, possibly even an irresponsible act once the vehicle is in motion.
The common problem found in existing navigation systems is that they require the vehicle operator to look at a map, or other means that contains directional information, on some sort of display that is outside the vehicle operator's normal field of view when the vehicle is in motion. In most cases, operators have to turn their heads to look sideways or downward to see the displays. This can make driving with such navigation system a challenging and hazardous task.
Some navigation systems have attempted to overcome this problem by providing synthesized speech feedback to the vehicle operator. However, such solutions are not always viable. For example, in the case of convertible vehicles or when the vehicle's windows are down with loud noises in the vicinity, any voice feedback is often inaudible. In other cases, such as during casual trips, vehicle operators may find such communications to be interruptive of their preferred silence, conduct of a conversation with a passenger, or listening to a radio or stereo.
Despite this prior art, the need exists for an improved vehicle navigation device with more precise position determining means and a proactive, driver-friendly interface that reduces diversions away from the driver's safe, attentive operation of the vehicle.